In many applications, there is a need to reduce a range over which an input resistance varies. For example, in an energy recovery system that uses a plurality of tuned rectifier circuits to convert an RF signal to DC, there may be a need to compress a resistance range looking into the various rectifier circuits into a smaller range. The compressed resistance may then be presented to an RF circuit as a resistive termination. In such applications, a resistance compression network may be provided to perform the compression. Some examples of resistance compression networks are described in U.S. Pat. No. 7,535,133 to Perreault et al., which is hereby incorporated by reference herein in its entirety.
As with most circuits and systems, it is generally desirable that resistance compression networks be relatively simple and inexpensive to fabricate. In addition, it is generally desirable that resistance compression networks have relatively low loss. It may also be desirable that such networks be capable of performing other functions in addition to resistance compression. As such, there is a need for resistance compression networks that are capable of providing some or all of these attributes.